CODEWITHSUNDEEP
javaspringspring-bootdependency-injectionautowired
Meena Chaudhary
Meena Chaudhary

Reputation: 10715

Injected Spring Bean is NULL in Spring Boot Application

I am using Spring Boot(1.5.3) to develop a REST Web Service. In order to take some action on incoming request I have added an interceptor shown below.

@Component
public class RequestInterceptor extends HandlerInterceptorAdapter {

@Autowired
RequestParser requestParser;


@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
        throws Exception {

    //HandlerMethod handlerMethod = (HandlerMethod) handler;
    requestParser.parse(request);
    return true;
}
}

RequestInterceptor has an autowired Spring Bean RequestParser responsible for parsing the request.

@Component
public class RequestParserDefault implements RequestParser {

@Override
public void parse(HttpServletRequest request) {

    System.out.println("Parsing incomeing request");
}

}

Interceptor registration

@Configuration  
public class WebMvcConfig extends WebMvcConfigurerAdapter  {  

@Override
public void addInterceptors(InterceptorRegistry registry) {
   registry.addInterceptor(new RequestInterceptor()).addPathPatterns("/usermanagement/v1/**");
}
}

And my Spring Boot Application

@SpringBootApplication
public class SpringBootApp {

public static void main(String[] args) {
    SpringApplication.run(SpringBootApp.class, args);

}
}

Now when a request comes in, it lands in preHandle method of RequestInterceptor but RequestParser is NULL. If I remove the @Component annotation from RequestParser I get an error during Spring context initialization No bean found of type RequestParser. That means RequestParser is registered as Spring bean in Spring context but why it is NULL at the time of injection? Any suggestions?

Upvotes: 2

Views: 3553

Answers (1)

Florian Fray
Florian Fray

Reputation: 274

Your problem lies in this new RequestInterceptor(). Rewrite your WebMvcConfig to inject it, e.g. like this:

@Configuration  
public class WebMvcConfig extends WebMvcConfigurerAdapter  {  

  @Autowired
  private RequestInterceptor requestInterceptor;

  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(requestInterceptor)
            .addPathPatterns("/usermanagement/v1/**");
  }
}

Upvotes: 3

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